Answer: a, b, d
If the production right recursive like S → A = S then ‘=’ is right associative.
If the production is left recursive like S → S + A then ‘+; is left associative.
Now see in problem
For ‘!’ production is C → C ! D, it is left recursive so operator is left associative.
For ‘*’ production is A → B * A, it is right recursive so operator is right associative.
For ‘&’ production is A → C & C, so we can’t comment about associativity since this production is neither left recursive or right recursive.
For ‘@’ production is B → B @ C, it is left recursive so operator is left associative.